It required the use of ephemeral IP address, which can be a waste of IP space

It only worked if there was one destination network, as Next-Hop Tunnel Bindings (NHTBs) did not address which source network traffic came from

Traffic selectors were introduced as feature starting in Junos 12.1X46-D10 (SRX200, SRX1400, and SRX3k series) and Junos 17.3R1 (SRX300, SRX1500, SRX4k, and SRX5k series) for IKEv1. IKEv2 support was added in Junos 15.1X49-D100, meaning this is only available for the SRX300, SRX1500, SRX4k, and SRX5k series.